Inflammatory bowel diseases (IBD) have become a significant public health problem due to the increase in the incidence of IBD, particularly Crohn's disease, in the U.S. population. The etiology of IBD is still unknown, however, previous studies, certain clinical manifestations and preliminary findings presented in this proposal give us clues to the possible mechanisms involved. Specifically, the microflora of the gut and the periodontium is unique and characteristic of patients with IBD. Concomitantly, severe periodontal disease has been noted as a characteristic feature in certain IBD patients. Since periodontitis is an infectious disease, we investigated the periodontal microflora of IBD patients and found it to be unique and uncharacteristic of periodontal diseases. The IBD periodontal microflora is composed almost completely of a small (less than 0.2u) motile, anaerobic Gram negative rod. The investigation of an etiologic role for infectious agents in IBD has produced conflicting results. Most of these studies, however, have been based upon the filtration of IBD material through 0.2u filters to eliminate bacterial cells. Hence, the finding of an organism less than 0.2u in size requires further investigation. It is the purpose of this study to begin characterizing the relationships between infectious agents and the pathogenesis of IBD. The specific aims of this proposal are 1) The nature and extent of pariodontal disease in IBD patients will be correlated to IBD disease activity. 2) The predominant cultivable gut and periodontal microflora will be compared and monitored for changes with disease activity and characterized by antimicrobial sensitivity. The goal of these investigations is to gain further knowledge of the structural and functional relationships of the inflammatory process by defining the complex interactions between the host and its environment, particularly microorganisms. The investigation of unique anaerobic microbes, in relation to neutrophil dysfunction, presents an opportunity to gain further insight into the etiology and pathogenesis of IBD.